Opening a two-day summit, President Barack Obama drew attention to contentious economic and cybersecurity issues Friday night as he warmly received Chinese President Xi Jinping to a California desert estate for high-stakes talks.

The NATO meeting in Chicago this weekend is a chance for alliance leaders to proclaim solidarity and promise success. But the gathering probably won’t resolve the underlying anxiety about sharing the burdens of defense, a concern heightened by Europe’s economic crisis and America’s growing weariness at carrying the heaviest load.